Hydrazine and other derivative hypergolic fuels are used as rocket propellants. The auxiliary power units on the Space Shuttle Orbiter used monomethylhydrazine (MMH) to provide power through hydrogen generation for electrolysis. The orbiters also used hydrazine derivatives in the Orbiter Maneuvering System (OMS) pods to orient the shuttle in space. Satellites, space planes, and other rocket payloads also consume hydrazine derivatives as fuel. Commercially, hydrazine is used as a polymerization catalyst, a blowing agent, an oxygen scavenger, and a reducing agent. Hydrazine is highly toxic, highly flammable, and even at very low concentrations can strongly irritate the nose, eyes, and throat. Dizziness, nausea, and death can result from the inhalation of hydrazine. Hydrazine gas is colorless making it difficult to visually detect; however, at 3-4 ppm, the odor of hydrazine is detectable by the human nose. Yet the acceptable concentration limits for human exposure are 4 ppm over one hour, 0.9 ppm from 1 day to 30 days, and 0.15 ppm for 6 months, meaning that once someone detects hydrazine or its derivatives via smell, the person has already been exposed to excessive, harmful concentrations.
Hazardous gas detection is critical for the safety of personnel and equipment. Current means for monitoring hypergolic fuel leakage is inadequate to accurately and quickly determine leaks, allowing personnel to be exposed to dangerous concentrations of hypergolic vapors. Because the acceptable exposure limits are extremely low for hydrazine and other derivative hypergolic fuels, a chemochromic detecting device would provide an immediate visual warning to the presence of hydrazine and other derivative hypergolic fuels, thus protecting personnel from dangerous chemical vapor ingestion.
Incorporated into a suitable product matrix, a chemochromic pigment adapted to change color in the presence of hypergolic vapors would provide a means for notifying personnel of their potential exposure to hypergolic leakage. The ability to manufacture Personnel Protective Equipment (PPE) having the capability to detect miniscule levels (up to ppb) of hydrazine and rapidly respond chemochromically in the presence of toxic chemicals would be of great use to personnel working with these chemicals.
As will be discussed in detail hereafter, the present invention is directed to a process for cost effectively synthesizing a chemochromic pigment that indicates the presence of hypergolic fuels, such as hydrazine, and incorporating said chemochromic pigments into a variety of articles including, but not limited to, tapes, paints, and textiles.